@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');
:root {
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --secondary: #10b981;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
  --radius: 12px;
}
* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Inter', sans-serif; }
body { background: var(--bg); color: var(--text-main); line-height: 1.6; overflow-x: hidden; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }

/* Navbar */
.navbar { position: fixed; top: 0; width: 100%; background: rgba(255,255,255,0.9); backdrop-filter: blur(10px); z-index: 1000; box-shadow: var(--shadow-sm); padding: 1rem 2rem; display: flex; justify-content: space-between; align-items: center; }
.logo { font-size: 1.5rem; font-weight: 800; background: linear-gradient(to right, var(--primary), var(--secondary)); -webkit-background-clip: text; color: transparent; }
.nav-links { display: flex; gap: 2rem; }
.nav-links a { font-weight: 500; transition: color 0.3s; position: relative; }
.nav-links a::after { content: ''; position: absolute; bottom: -5px; left: 0; width: 0; height: 2px; background: var(--primary); transition: width 0.3s; }
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }
.hamburger { display: none; font-size: 1.5rem; cursor: pointer; color: var(--text-main); }

@media (max-width: 768px) {
  .nav-links { display: none; flex-direction: column; position: absolute; top: 100%; left: 0; width: 100%; background: var(--surface); padding: 2rem; box-shadow: var(--shadow); text-align: center; }
  .nav-links.active { display: flex; }
  .hamburger { display: block; }
}

/* Base Layout */
.container { max-width: 1200px; margin: 0 auto; padding: 7rem 2rem 3rem; }

/* Typography & Buttons */
.title { font-size: 2.5rem; font-weight: 700; margin-bottom: 1.5rem; text-align: center; }
.subtitle { text-align: center; color: var(--text-muted); margin-bottom: 3rem; font-size: 1.1rem; }
.btn { display: inline-block; padding: 0.8rem 2rem; background: var(--primary); color: white; border-radius: 8px; font-weight: 600; border: none; cursor: pointer; transition: all 0.3s; text-align: center; }
.btn:hover { background: var(--primary-hover); transform: translateY(-2px); box-shadow: var(--shadow); }
.btn-outline { background: transparent; border: 2px solid var(--primary); color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: white; }

/* Hero Section */
.hero { display: flex; flex-direction: column; align-items: center; text-align: center; padding: 4rem 0; animation: fadeIn 1s ease-out; }
.hero h1 { font-size: 3.5rem; font-weight: 800; line-height: 1.2; margin-bottom: 1rem; }
.hero h1 span { color: var(--primary); }
.hero p { font-size: 1.2rem; color: var(--text-muted); max-width: 600px; margin-bottom: 2rem; }
@media (max-width: 768px) { .hero h1 { font-size: 2.5rem; } }

/* Grid Components */
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 2rem; margin-top: 2rem; }
.card { background: var(--surface); padding: 2rem; border-radius: var(--radius); box-shadow: var(--shadow); transition: all 0.3s; }
.card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }
.card h3 { font-size: 1.25rem; font-weight: 600; margin-bottom: 1rem; color: var(--text-main); }
.card p { color: var(--text-muted); margin-bottom: 1.5rem; }

/* Feature Cards */
.feature-icon { font-size: 2.5rem; margin-bottom: 1rem; }

/* Timetable Filtering */
.filter-tabs { display: flex; justify-content: center; gap: 1rem; margin-bottom: 2rem; border-bottom: 2px solid #e2e8f0; padding-bottom: 1px; }
.tab-btn { padding: 0.8rem 2rem; background: transparent; border: none; border-bottom: 2px solid transparent; margin-bottom: -2px; font-size: 1.1rem; font-weight: 600; color: var(--text-muted); cursor: pointer; transition: all 0.3s; }
.tab-btn.active { color: var(--primary); border-bottom-color: var(--primary); }

.filter-group { display: flex; gap: 0.5rem; justify-content: center; flex-wrap: wrap; margin-bottom: 2rem; }
.filter-btn { padding: 0.5rem 1.2rem; border: 1px solid #cbd5e1; background: var(--surface); color: var(--text-muted); border-radius: 20px; font-weight: 500; cursor: pointer; transition: all 0.2s; }
.filter-btn:hover, .filter-btn.active { background: var(--primary); border-color: var(--primary); color: white; }

.class-card { background: var(--surface); padding: 1.5rem; border-radius: var(--radius); box-shadow: var(--shadow-sm); border-left: 4px solid var(--primary); position: relative; overflow: hidden; animation: slideUp 0.4s ease-out forwards; opacity: 0; }
.class-meta { display: flex; align-items: center; gap: 1rem; color: var(--text-muted); font-size: 0.9rem; margin-top: 0.5rem; margin-bottom: 1rem; }
.class-tag { display: inline-block; padding: 0.3rem 0.8rem; background: #e0e7ff; color: var(--primary); border-radius: 12px; font-size: 0.8rem; font-weight: 600; }
.class-type { position: absolute; top: 1.5rem; right: 1.5rem; font-size: 0.8rem; font-weight: 700; color: var(--secondary); background: #d1fae5; padding: 0.2rem 0.6rem; border-radius: 12px; }

/* Forms & Tools */
.tool-box { background: var(--surface); padding: 3rem; border-radius: var(--radius); box-shadow: var(--shadow-lg); max-width: 700px; margin: 0 auto; }
.form-group { margin-bottom: 1.5rem; text-align: left; }
.form-group label { display: block; margin-bottom: 0.5rem; font-weight: 600; color: var(--text-main); }
.form-control { width: 100%; padding: 0.8rem 1rem; border: 1px solid #cbd5e1; border-radius: 8px; font-size: 1rem; outline: none; transition: border-color 0.3s; background: var(--bg); }
.form-control:focus { border-color: var(--primary); background: var(--surface); box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1); }

.schedule-result { margin-top: 2rem; padding: 1.5rem; background: #f8fafc; border-radius: 8px; border: 1px dashed #cbd5e1; }
.schedule-item { display: flex; justify-content: space-between; padding: 0.8rem; border-bottom: 1px solid #e2e8f0; }
.schedule-item:last-child { border-bottom: none; }

/* Contact Specific */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 3rem; }
@media (max-width: 768px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-info { display: flex; flex-direction: column; gap: 1.5rem; }
.info-item { display: flex; align-items: flex-start; gap: 1rem; }
.info-icon { background: #e0e7ff; color: var(--primary); padding: 0.8rem; border-radius: 50%; font-size: 1.2rem; }

/* Footer */
footer { background: white; padding: 3rem 2rem 2rem; margin-top: 5rem; border-top: 1px solid #e2e8f0; text-align: center; color: var(--text-muted); }

/* Animations */
@keyframes fadeIn { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
@keyframes slideUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }